Poly (lactic acid) is one of the most studied biodegradable polymers, mainly due to their good mechanical properties and its easy production of the monomer (lactic acid). Moreover, the PLA can be readily processed similar to the polyolefins. Despite these advantages, their application range is still limited by their high cost of production, its brittleness and its poor thermal stability. The objective of this study was to investigate the effect of adding the calcium carbonate nanofiller on the rheological properties of PLA. PLA (INGEO 2003D) was supplied by Natureworks LLC. The nanofiller n-CaCO3 was donated by Nano Materials Technology. The filler used was surface coated with stearic acid. The composites were processed in a twin-screw co-rotating extruder (TeckTril, model DCT-20) with 20 mm diameter and L/D=36. The temperature profile set at 45°C/210/210/220/220/210/200/200/200/190°C. The obtained extrudates were later pelletized and subsequently kept for drying at 60°C. Dynamic rheological properties were assessed using an oscillatory rheometer (AR 2000, TA Instruments). All composites produced showed a Newtonian behavior throughout the frequency range analyzed. Results from complex viscosity and G’, G” versus frequency curves showed that when 7 wt% of nanofiller was added, at frequency values up to around 1,6 rad/s, higher G’ values was obtained, indicating that the composite with higher nanofiller content presents a higher elastic behavior in relation to the other composites at lower frequency range. As frequency increases, a slight change in the chain dynamics occurred, and lower G’ values were obtained, i. e., the composite with 7 wt% of n-CaCO3 showed a more viscous behavior in relation to neat PLA and PLA/n-CaCO3 with 5 wt% of filler. The results also show that the composite with 3 wt% of n-CaCO3 presented the lower G’ values, indicating a more viscous behavior in relation to other composites analyzed.